Rabies virus matrix protein interplay with eIF3, new insights into rabies virus pathogenesis

Viral proteins are frequently multifunctional to accommodate the high density of information encoded in viral genomes. Matrix (M) protein of negative-stranded RNA viruses such as Rhabdoviridae is one such example. Its primary function is virus assembly/budding but it is also involved in the switch from viral transcription to replication and the concomitant down regulation of host gene expression. In this study we undertook a search for potential rabies virus (RV) M protein's cellular partners. In a yeast two-hybrid screen the eIF3h subunit was identified as an M-interacting cellular factor, and the interaction was validated by co-immunoprecipitation and surface plasmon resonance assays. Upon expression in mammalian cell cultures, RV M protein was localized in early small ribosomal subunit fractions. Further, M protein added in trans inhibited in vitro translation on mRNA encompassing classical (Kozak-like) 5′-UTRs. Interestingly, translation of hepatitis C virus IRES-containing mRNA, which recruits eIF3 via a different noncanonical mechanism, was unaffected. Together, the data suggest that, as a complement to its functions in virus assembly/budding and regulation of viral transcription, RV M protein plays a role in inhibiting translation in virus-infected cells through a protein–protein interaction with the cellular translation machinery

Home range overlap, matrilineal and biparental kinship drive female associations in bottlenose dolphins

Few studies of kinship in mammalian societies have been able to consider the complex interactions between home range overlap, association patterns and kinship, which have created a critical gap in our understanding of social evolution. We investigated the association patterns of female bottlenose dolphins, Tursiops aduncus, in the eastern gulf of Shark Bay, Western Australia and found that they depended upon the complex interplay of at least three factors: home range overlap, matrilineal kinship and biparental kinship. While home range overlap was positively correlated with female association patterns, preferred associations were found between females showing as little as 27% home range overlap, and some pairs showed avoidance despite 100% home range overlap. Furthermore, on average, both casual and preferred associations took place between females that were more closely biparentally related than expected by chance and this pattern varied depending upon whether or not pairs of females shared the same matriline

The relative importance of reproduction and survival for the conservation of two dolphin populations

It has been proposed that in slow-growing vertebrate populations survival generally has a greater influence on population growth than reproduction. Despite many studies cautioning against such generalizations for conservation, wildlife management for slow-growing populations still often focuses on perturbing survival without careful evaluation as to whether those changes are likely or feasible. Here, we evaluate the relative importance of reproduction and survival for the conservation of two bottlenose dolphin (Tursiops cf aduncus) populations: a large, apparently stable population and a smaller one that is forecast to decline. We also assessed the feasibility and effectiveness of wildlife management objectives aimed at boosting either reproduction or survival. Consistent with other analytically based elasticity studies, survival had the greatest effect on population trajectories when altering vital rates by equal proportions. However, the findings of our alternative analytical approaches are in stark contrast to commonly used proportional sensitivity analyses and suggest that reproduction is considerably more important. We show that 1. in the stable population reproductive output is higher, and adult survival is lower; 2. the difference in viability between the two populations is due to the difference in reproduction; 3. reproductive rates are variable, whereas survival rates are relatively constant over time; 4. perturbations on the basis of observed, temporal variation indicate that population dynamics are much more influenced by reproduction than by adult survival; 5. for the apparently declining population, raising reproductive rates would be an effective and feasible tool to reverse the forecast population decline; increasing survival would be ineffective. Our findings highlight the importance of reproduction – even in slow-growing populations – and the need to assess the effect of natural variation in vital rates on population viability. We echo others in cautioning against generalizations based on life-history traits and recommend that population modeling for conservation should also take into account the magnitude of vital rate changes that could be attained under alternative management scenarios